The constantly meshed type multi-stage transmission has a configuration in which one of the drive gears and the driven gears are fixed on a gear shaft, while the other of the drive gears and the driven gears are rotatably supported on another gear shaft, and in which one of the rotatably supported gears is selected to be engaged with the other gear shaft by an engaging means, to make a gear shift.
There is a patent publication disclosing a multi-stage transmission by the present applicant, in which engaging pawls driven by cam members are used for the engagement between the gear and the gear shaft (Patent Document 1).
[Patent Document 1]
Japanese Patent No. 3838494
The transmission disclosed in Patent Document 1 has a structure in which a cam member (clutch operating element) formed with a cam groove is axially moved in a hollow gear shaft (transmission shaft) rotatably supporting gears thereon, and pin members penetrating the wall of the hollow gear shaft are thereby moved radially outwards and inwards to cause free ends of ratchet pawls fitted in an inner peripheral part of the gear to project or retract from the inner peripheral surface. When the free ends of the ratchet pawls are projected, they are engaged with gear teeth formed on the hollow gear shaft so as to transmit rotation in one direction, and when the ratchet pawls are retracted, the engagement is released.
An end part of the cam member is engaged with a shift plate, and turning of the shift plate moves the cam member in the axial direction.
Besides, turning of a cable winding member, around which a cable to be manipulated by the driver is wound, is transmitted to the shift plate through a lost motion mechanism.